OROVILLE, Calif. — A highway overpass that was under construction collapsed Tuesday, crushing a delivery truck and injuring a construction worker who clung to a steel beam as it tumbled 50 feet to the ground.

Firefighters swarmed the FedEx delivery truck to cut its driver from underneath a large steel beam that crushed the hood but missed the cab. A second beam landed on the back of the truck.

The cause of the collapse was being investigated.

The driver, Robert Sylvester, 46, of Chico, was pulled free about 2½ hours after he was trapped. Janet Upton, a spokeswoman for the California Department of Forestry and Fire Protection, said Sylvester suffered injuries to his lower extremities but was able to talk with rescuers as they extracted him.

Sylvester was in good condition after being airlifted to Enloe Medical Center in Chico, hospital spokeswoman Sharon Cuglietta said.

Fractured pelvis, elbow, leg for workerThe construction worker, Jeffrey Doll of Olivehurst, who was on top of the structure, also was injured when it collapsed about 7:15 a.m.

“He rode it 50 feet down to the ground. It’s incredible that he’s going to survive that one,” said Mark Dinger, a spokesman for the California Department of Transportation.

Doll, 39, was in serious condition with a fractured pelvis, fractured left elbow and broken lower left leg, officials said.

The overpass was being built over Highway 149 where it intersects with Highway 70, about an hour north of Sacramento, patrol spokesman Karen Ogle said. The project began last summer and was scheduled to be completed in fall 2009.

Highway 149 had been closed overnight and until 5 a.m. Tuesday while workers from private contractor FCI Constructors Inc. erected concrete columns and steel tubes weighing 2,400 to 3,000 pounds that were held together with cables and steel I-beams, Dinger said.

FCI has no record of health and safety violations, and a random inspection in July 2005 found no infractions, said Kate McGuire, a spokeswoman with the state Division of Occupational Safety and Health.

FCI Constructors President Curtis Weltz, who arrived at the site after the collapse, said both the contract employee and the truck driver would be fine.

“At this point, we do not have the cause of the incident,” Weltz said. “There’s a bunch of different possible scenarios. It’s never happened to us before.”

FedEx packages damagedConstruction crews planned to stabilize the remaining structure and remove an estimated 70 tons of steel worth about $50,000 that crashed onto the highway.

“The top priority right now is to stabilize this and get it reopened to traffic,” Dinger said.

Meanwhile, FedEx was evaluating the “large number of packages” damaged in the accident.

“When it is deemed safe and all official investigations are complete, the packages will be retrieved and returned to our local facility,” said spokesman Robert Boulware.

The Department of Transportation was rerouting traffic until the road could be reopened, possibly as early as Wednesday morning.